In order to provide colour-changing cosmetic products, in particular for keratin fibres, such as hair for example, a person skilled in the art is aware of various dye systems depending on the demands placed on the colouring. For permanent, intense colouring with corresponding fastness properties, what are known as oxidation dyes are used, which are generally provided in two parts. Here, an alkaline preparation of what are known as oxidation dye precursors (ODPs) is used as first part and contains what are known as developer components and coupler components, which form the actual dyes with one another under the influence of oxidising agents, such as hydrogen peroxide. The oxidising agent preparation, as second part, which is often also referred to as a developer, contains at least water and hydrogen peroxide and is set to an acidic pH for stability reasons.
The oxidising agent preparation set to an acidic pH is mixed with the alkaline part, which is set to an alkaline pH just before use, usually in a ratio by weight of first part (set to an alkaline pH) to oxidising agent preparation of from about 1:1 to about 1:2. This mixture for use is applied to the hair, left there usually for approximately 30 to 45 minutes, and is then rinsed out. During this time, the oxidation dye precursors (ODPs) react with one another under the influence of the hydrogen peroxide to form oligomers, wherein the desired hair colour develops.
Conventional colorants consist of a liquid oxidising agent and a colour cream.
Document WO 03/089330 A1 discloses a permanent hair dye composition in which the developer and oxidising agent dye constituents are disposed in a flexible two-chamber container, which allows both dye constituents to be pushed out using the fingers.
DE 4436863 C1 and DE 4436862 describe two-chamber containers for hair colorants which enable the dye constituents to be dosed by a mechanical closure system. The containers described in these documents have the disadvantage that, at the end, a container remains which has to be disposed of. Furthermore, the use of hydrogen peroxide as oxidising agent is described in both documents, however this, as liquid component, if handled incorrectly, for example if it comes into contact with the skin or eyes, can lead to irritations or in extreme cases can even trigger allergies.
Document WO 2016/074853 A1 discloses a cosmetic product for dyeing keratin fibres, in which one of the components is packaged in a water-soluble film and the other component is again an aqueous oxidising agent solution.